1. Field of the Invention
The present invention relates to using a satellite communication system to provide a cost-effective way of routing remote telemetry data to customers and, more particularly, to receiving telemetry data in a simplex mode along with normal traffic.
2. Description of the Related Art
What is the inventory level of your remote storage tank? The level and water-quality of your water tank? Where and when did your rail car deliver last? These are important questions for many industrial operations. There is a need for a cost-effective way to collect basic environmental and industrial data in real time. Applications include remote monitoring of water and fuel tanks, pipelines, or electric power lines, as well as asset tracking of shipping containers or construction equipment. Not that long ago, keeping track of remote assets involved people going out in the field and recording data with pencils and paper. Later, computer systems were used to monitor remote assets, but it still was not satisfactory. Too much time is wasted in determining what remote assets are where and collected data often becomes obsolete after too much delay. There is a need for a satellite communication system that provides a cost-effective service for gathering, processing, and routing remote asset data to customers over an Internet connection.
Some satellite communication systems are too expensive and complex. Some do not provide this service in real time and have significant latency. Some systems have a kind of polling sequence that introduces a delay from the time data is ready to transmit to the time it is allowed to be transmitted. Some have duplex communication and do processing on-board, which are not necessary. There is a need for near real-time data delivery, i.e., no delay or negligible delay. Certain remote telemetry applications cannot tolerate latency. Some systems provide both monitoring and controlling remote assets at a complexity and cost that is intolerable for many remote assets. For these types of assets, the customer is only interested in data on an infrequent basis. Since the amount of data delivered to the customer is low and infrequent, a low cost alternative to existing systems is needed. In addition, once some systems are in place, they cannot add a new service like this later. Therefore, there is a need for a satellite communication system that provides a cost-effective way to gather, process, and route remote asset data to customers over an Internet connection in addition to its regular service.
The present invention augments an existing satellite communication system with a low data rate, low cost system for gathering, processing, and routing remote asset data to customers over an Internet connection. The present invention also reduces system noise and improves system performance.
The present invention has many advantages, including the following. Unlike costly, complex, and slow conventional systems, the present invention offers services in real time. In addition, most existing systems are duplex systems that are used for both monitoring and controlling remote assets. This is done at a complexity and cost that cannot be tolerated for many remote telemetry applications that infrequently route the status, condition, or location of remote assets to a customer. The present invention also provides superimposition of a simple protocol over existing infrastructures to provide a low cost solution to monitoring remote assets. Repeating transmissions and allowing for variable length messages is a relatively low cost way for the present invention to increase the robustness of system performance. Additional advantages over conventional systems are using a priori satellite ephemeris data to compensate for Doppler shift and selectively turning various inputs on or off to reduce system noise and improve system performance. Furthermore, adapting the existing satellite communication infrastructure to provide the additional service of routing remote telemetry data is done quickly, easily, and at very low recurring and non-recurring developmental costs.